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r. <br />' • • III IIIIIIIIIIIII III <br />TRAPPSB mll~tp6 IBC. 999 <br />,~,._ <br />August 2, 1995 <br />FAX DELIVERY <br />HARD COPY VIA CERTIFIED MAIL 2067066341 <br />Mr. Jce Dudash <br />Colorado Division of Minerals & Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />Deaz Mr. Dudash: <br />Enclosed is a revised estimate of Trapper Mining Inc.'s average annual water depletion to the <br />Yampa River. The enclosed information is being submitted in response to comments by Keith <br />Rose of USFWS concerning potential water depletion impacts to endangered fish in the <br />Colorado River system. The evaporative loss depletion assumes a "worst case" where all ponds <br />aze always at spillway elevation. The revised estimate includes an average annual evaporative <br />loss for the two ponds proposed for construction in TR-67. The estimate also includes a pro- <br />jected average annual water depletion for all sediment ponds and livestock tanks forecast for <br />construction during the remainder of the Trapper Mine life. This assumption is also "worst <br />case" in that future ponds to be constructed are included but future pond removals are not. <br />Water depletion due to road watering at Trapper is based on the annual average water use from <br />1989 to 1994. This approximate intensity of road watering is expected to continue in future <br />years and could possibly even decrease as a result of recent increased use of chemical dust <br />suppressants. <br />Note that ground water pumped from deep pit aquifers and dewatering wells is subtracted from <br />the water depletion estimate as this water augments surface water discharges. The estimates of <br />ground water discharges are based on actual monitoring data collected from 1990 through <br />1994. <br />In comparing the revised, 1995 estimate to the original 1988 estimate (enclosed), note that the <br />1995 estimate is nearly identical to 1988 even though several "worst case" evaporative loss <br />assumptions were made. <br />P.O. Box 187 Craig, Colorado 81626 (303) 824-4401 <br />